Hasnat Khan, the man who was widely regarded as Princess Diana’s greatest love, is to marry a fellow heart surgeon.

The 51-year-old, whom the late Princess called her ‘Mr Wonderful’, has become engaged to Alexandra Panagoulas, who is 21 years his junior.

After meeting his new love through work, Dr Khan says he is "happier than he’s been in ages".

Hasnat reluctantly ended his two-year relationship with Diana just a few months before she died in 1997. One of her closest friends revealed she was "very much in love with him... and wanted to marry him".